1. Field of the Invention
This invention pertains generally to devices for separating items by introducing the items into a fluid flow path. This invention also pertains generally to devices and systems for separating debris from items. The preferred embodiments of the invention have specific relevance to apparatus for separating debris from produce, such as potatoes, sweet potatoes, sugar beets, carrots, and any other commodity or material having a specific gravity greater than one, the most preferred embodiments pertaining to--the separation of debris--e.g., vines, grass, defective potatoes, plastic, dirt, and/or rocks from potatoes. The invention can also be used to separate a variety of other product, such as apples, oranges, other citrus fruit and product having a specific gravity less than one.
2. Description of the Related Art
Typically, when potatoes or the like are gathered from a farm site, various debris is unavoidably collected along with the potatoes. The type of debris depends, in part, upon the soil and farm conditions; however, such debris typically includes one or more of the following: vines, grass, defective potatoes, plastic materials used in potato fields, dirt and/or rocks. Often, the ratio of debris to potatoes is on the order of about 1/3. Accordingly, separation of such debris is critical. When farmers sell such potatoes to end users--e.g., manufacturers of potato chips, french fries, and the like--such end users typically demand, that such potatoes be virtually free of such debris. A few items of debris in a single delivery can result in a lost sale and/or can even lead to the farmer's need to compensate the end user for costs related to such lost sale. As a result, considerable efforts are applied by farmers to remove such debris. This debris is usually removed manually. However, the amount of potatoes or the like processed is often a very large number. A farmer often must hire even about 30 people to work at the same time to separate unwanted debris from the potatoes.
Similar problems exist with other produce such as sugar beets, carrots, sweet potatoes and the like. There has been a need for an apparatus which can accurately separate debris from potatoes and the like. Existing systems which have been developed for the automation of debris elimination have a variety of problems--making their use less desirable, impracticable and/or impossible.
One known system is shown in U.S. Pat. No. 4,759,841 (Flodin). The '841 patent shows a density-current method and apparatus for separating produce, such as potatoes, from debris. In this system, an elongated tank has a water current directed from an inlet at one end wall. Products are conveyed into the tank by a conveyor adjacent to the inlet. As a result, the products introduced into the water stratify, due to their different densities. This device has a number of drawbacks, such as inability to handle a large quantity of produce at a single time, inability to maintain cleanliness of the water in the tank, inefficient separation capabilities and non-adaptability.
A variety of other systems are also known for the separation of various items in a fluid medium. However, all of the existing systems have substantial drawbacks and/or are inapplicable to certain uses contemplated by the present invention. There is still a great need for a device that will enable farmers to overcome the problems inherent with existing methods of removing debris from potatoes--which to this date, has largely been performed by substantial manual labor. In addition, there still remains a need for a permanently installed separation apparatus, such as at a processing plant which receives and processes potatoes and the like items.